CYB003: Deuterated Psilocybin Analog

CYB003 is a proprietary molecule derived from psilocybin, which is part of a family of molecules called indolamines that includes more common neurotransmitters like serotonin. CYB003 is being evaluated for the potential treatment of Major Depressive Disorder (MDD) and Alcohol Use Disorder (AUD) and is the first ever deuterated psilocybin analog to enter clinical development.

Cybin is currently conducting a Phase 1/2a clinical trial evaluating CYB003 in people with MDD.

CYB003 Development Highlights

Cybin’s focus is on developing CYB003 as an improved therapeutic deuterated psilocybin analog to achieve better outcomes for patients and providers.   

CYB003 is a new chemical entity (NCE) designed to achieve:

  1. Fast onset and short duration of effect
  2. Low variability in plasma levels
  3. Effects at low doses
  4. Potentially faster and sustained therapeutic outcomes compared to existing treatments

Based on its mechanism of action, the psychedelic effects of CYB003 indicate the potential to treat MDD and AUD and provide potentially faster and sustained therapeutic outcomes compared to treatments currently available. 

In February 2023, Cybin announced interim data from its ongoing Phase 1/2a clinical trial  

In February 2023, Cybin announced interim data from its ongoing Phase 1/2a clinical trial  

Less Variability in plasma levels
Faster onset of
Shorter duration of effect
Potentially better tolerability

CYB003 Demonstrates Promising Clinical Results

Based on an interim analysis of CYB003 in healthy volunteers: 

CYB003 was rapidly absorbed and rapidly cleared with low variability in plasma levels 

Psychedelic effects of CYB003 were seen within 15 minutes and average duration of peak effects lasted two hours 

Psychedelic effects consistent with therapeutic efficacy were reported in the majority of participants at the higher dose levels 

Single oral doses of CYB003 were well-tolerated with only mild to moderate adverse events reported, and no serious adverse events were observed 

CYB003 Demonstrates Promising Preclinical Results

CYB003 could potentially reduce clinic time for patients by 50%


Time (Hours)

0          0.2          0.4          0.6          0.8           1

CYB003 onset of action is 2X as fast as oral

Time (Hours)

0                 1                 2                 3                  4

CYB003 duration effects are cut in half compared to oral psilocybin

Upon ingestion, psilocybin is rapidly converted to psilocin, which acts as a partial agonist for 5-HT2A receptors with effects lasting 4-6 hours. Psilocybin analogs such as CYB003, are specifically engineered to bind 5-HT receptors with better affinity. As a result, CYB003’s onset of action is faster, and the duration of effect is shorter acting, therefore improving convenience for clinical setting administration. 

CYB003 Could Have Potentially Reduced Side Effects


Brain to Plasma Ratio of Active Agent

0          2          4          6          8          10          12

Improved brain to plasma ratio could result in therapeutic effects at lower doses and less side-effects

People metabolize psilocybin at different speeds, making it difficult to find one dose that works for all patient groups. Therefore, there is strong demand for molecules with similar therapeutic properties but more controlled pharmacokinetic profiles. Encouraging preclinical data demonstrated CYB003 plasma concentration profiles were less variable than psilocybin and had improved brain penetration ratios. The data suggests CYB003 could result in therapeutic effects with safer dosing options and more predictable patient outcomes.